This invention relates, in general, to automotive diagnostic tools, and more particularly, to an automotive diagnostic tool which receives information from an automotive computer of an automobile.
The automobile has played an important role in increasing the range in which a human is able to travel on a daily basis. In fact, the automobile has permeated our society to the extent that we have become reliant on the automobile for our transportation needs. The automobile became an indispensable part of daily life when its price was reduced to an affordable level for the average working man and woman. Still, the purchase of an automobile is not a trivial issue, other than the purchase of a home, it is typically the next most expensive purchase made.
In the past, maintaining and repairing an automobile was a popular way to reduce the cost of owning an automobile. The mechanical nature of the automobile allowed one to understand its operation without significant special training. This is no longer true in a modern automobile even though the principles of operation are still the same. The increased complexity of the automobile resides in the addition of electronics to control every facet of automobile operation. The use of microprocessors and sensor technology throughout a car has allowed much finer control of its operation thus allowing today's automobile to provide more power with greater fuel efficiency while reducing the amount of toxic emissions. The addition of electronics has also discouraged most people from maintenance and repair because the electronics must be interfaced to diagnose a problem. The equipment used by professional automotive technicians to interface with the electronics of an automobile is cost prohibitive (typically greater than one thousand dollars) for someone wanting to tune-up or make minor repairs on one or two vehicles. Moreover, the average person is intimidated because he or she has little or no knowledge on how electrical devices operate (such as a microprocessor) or how the electronic system controls the automobile.
The integration of semiconductor devices within an automobile has mirrored the development and advancements of the semiconductor industry. Electronics have permeated every facet of the automobile, from fuel pumps to engine control. Microcontrollers are used extensively throughout an automobile to more efficiently operate all mechanical functions. No better example of this technical sophistication is the engine management system of an automobile. The engine computer rapidly senses engine parameters via sensors such as exhaust, air intake, fuel, temperature etc. and makes adjustments to minimize exhaust pollution, minimize fuel consumption, and maximize engine power. The results have been dramatic, today's automobile provides far more luxury, reliability, efficiency, and safety than its brethren of just a few years ago.
An automotive microcontroller is also used as a diagnostic tool for indicating problems. Data from sensors used on the automobile provide information that is stored by a microcontroller when an event occurs which is outside normal operating parameters. Also, the microcontroller can be used to take a "snapshot" of the output of each sensor at a particular point in time while an automobile is operating. In general, the microcontrollers are programmed to identify problems and to output data which would indicate a course of action in the repair of an automobile. The information stored on the microcontroller is ported out for analysis. For example, information from an engine management system is downloaded for providing data on the spark, fuel, air intake, or exhaust of an automobile. The information is used to determine if the engine is operating correctly. The automotive microcontroller can also be programmed to recognize specific faults based on the operating information. The identified fault is stored in memory as a fault code which can be received with the operating information to help diagnose a problem. Information on fault codes are typically written in a service manual for an automobile. A service manual defines each fault code and suggests potential sources for each problem associated with a fault code which greatly aids in the diagnosis of a problem.
Automotive diagnostic tools currently offered in the marketplace for interfacing with an automotive computer are tailored for the professional auto mechanic. In general, an automotive diagnostic tool is designed to be a permanent piece of hardware in an automobile repair facility. Most automotive diagnostic tool are not truly portable, for example, some are built on a cart for easy mobility and for providing a large readout screen but cannot easily be carried from location to location. An automotive diagnostic tool also is typically powered from a standard AC wall outlet since they are used on a continuous basis. The mobility is thus limited to the length of the power cord.
A typical auto mechanic works on a wide variety of automobiles. An automotive diagnostic tool for the professional mechanic must have the capability of interfacing with each type of automotive computer used by automobile manufacturers to provide full service. A further complication is the fact that each automobile manufacturer has its own interface and methodology for handling information. Also, it is quite common for an automobile to have more than one microcontroller. Microcontrollers are used to control everything from the power seats, radio, and climate control system to the mechanical operation of the engine and transmission. The professional auto mechanic requires access to all this information to provide complete service. One common approach for storing the information on interfacing with different automobile types is to place it on a Read Only Memory (ROM) cartridge. The ROM cartridge is then plugged into an auto diagnostic tool. The cost of the auto diagnostic tool is increased when the cost of additional ROM cartridges are factored in. A new ROM cartridge is purchased yearly that includes updated information on new model cars.
The cost of owning a professional automobile diagnostic tool is prohibitive to an average car owner concerned with maintaining one or two different automobiles. Moreover, the level of electronic sophistication provided by the professional automobile diagnostic tool in accessing all information available from an automotive computer system would be overwhelming to someone interested in diagnosing items of simple repair or maintaining an automobile in optimum running condition.
It would be of great benefit if an automobile diagnostic tool could be provided that was inexpensive, yet allowed a person of average mechanical skill to access information on an automotive computer for providing general maintenance on an automobile.